• 한국철도학회논문집
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• 제10권2호
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• pp.124-130
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• 2007

The emphasis of this paper is to find out the changes in length of nose in line with speed improvement and changes of the tendency in the shape of the nose in line with time series based on the Shinkansen vehicle. The length of the nose on the lines of high speed tends to get longer, however there is no proportion between the speed and the nose according to optimal design that was designed to reduce micro-pressure wave and air resistance. The Shinkansen vehicles, according to the shape, can be classified in to an Advanced Paraboloid shape, a Sharp-nosed shape, a Flat-nosed shape and an Organic Double-edged shape and is gradually changing in the trend of diversity and distinction. Hereafter, the design of the nose will be developed better into the design that will comprehend identity of manufacturer, region and culture on the basis of optimized aerodynamic shape.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 추계학술대회 논문집
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• pp.1835-1842
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• 2007

The purpose of this paper describes the changes of TGV & ICE series' nose shape by increasing train speed and according to the periodical characteristics. As the speed increases, the length of the nose shape trends to lengthen longer. But the nose shape length does not increase as speed improves by optimized nose shape to reduce aerodynamic drag and micro-pressure wave in tunnels. TGV & ICE series' nose shape can be classified into Advanced paraboloid type, Shape-nosed type, Organic double-edged type and Flat-nosed type by the advance research(the changes of Shinkansen vehicle' nose shape) of high speed railway. Because it trends to be diversified and characterized more and more. This paper analyzed and introduced as TGV & ICE series' nose shape by top 2 nation (Germany, France) and high speed railway in the past years(1980-2007) for their railway design trends by new positioning(Advance research).

• 한국철도학회:학술대회논문집
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• 한국철도학회 1998년도 창립기념 춘계학술대회 논문집
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• pp.596-603
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• 1998

The entry compression wave, which is generated at the entrance of the tunnel, is almost always associated with the pressure transients in the tunnel as well as the impulse noise at the exit of the tunnel. It is highly required to design the train nose shape that can minimize such undesirable phenomena. The objective of the current work is to investigate the effects of the train nose shape on the entry compression wave. Numerical computations were applied to one-dimensional unsteady compressible flow in high-speed railway train/tunnel systems. A various shape of train noses were tested for a wide range of train speeds. The results showed that the strength of the entry compression wave is not influenced by the train nose shape, but the time variation of pressure in the entry compression wavefront is strongly related to the train nose shape. The current method of the characteristics was able to represent a desirable nose shape for various train speeds. Optimum nose shape was found to considerably reduce the maximum pressure gradient of the entry compression wave.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 춘계학술대회 논문집
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• pp.2218-2223
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• 2008

A nose shape is strongly related with the aerodynamic performances of train. Therefore shape definition and aerodynamic performance analysis are important for train nose shape design. In this study, a new design method was suggested for train nose shape design by configuration function. To this end, the nose shape was classified by box type and each box shape is defined. After that the 3-D shape of train was defined as several mathematical functions by combination of each box shape. Also it was shown that the wind shield of driver's seat and complex curves of surface can be expressed using superposition of functions. This methodology can be used for grid generation of numerical analysis, and applied to aerodynamic optimization design of nose shape.

• 한국시뮬레이션학회논문지
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• 제27권3호
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• pp.109-116
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• 2018

견고표적을 무력화하기 위해서는 높은 침투/관통성능을 가진 침투탄의 개발이 필수적이다. 침투탄의 설계를 위해, 본 논문에서는 노즈 형상 인자들이 침투자의 콘크리트 침투/관통성능에 미치는 영향을 분석하였다. 전산해석은 상용 전산해석 프로그램인 AUTODYN-2D를 사용하여 수행하였다. Forrestal의 시험결과를 사용하여 전산해석의 신뢰성을 검증하였으며, 침투자의 노즈 형상보다는 노즈 길이가 침투/관통성능에 더 큰 영향을 미치는 것을 확인하였다. 또한, 침투자의 노즈 길이가 일정할 경우, 노즈 팁 직경을 특정값까지 증가시켜 침투/관통성능을 향상시킬 수 있음을 확인하였다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2005년도 추계학술대회 논문집
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• pp.94-100
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• 2005

This paper describes the changes of Shinkansen vehicles' nose shape by increasing train speed and according to the stream of time. As the speed increases, the length of the nose trends to lengthen longer. But the nose length does not increase as speed improves by optimized nose shape to reduce aerodynamic drag and micro-pressure wave in tunnels. Shinkansen vehicles nose shape can be classified into Advanced paraboloid type, Sharp-nosed type, Organic double-edged type and Flat-nosed type. In addition, it trends to be diversified and characterized more and more. In the near future, nose designs will be emphasized by the design concept including identity of each JR company based on optimized aerodynamic shape.

• 한국철도학회논문집
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• 제18권4호
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• pp.279-288
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• 2015

다양한 3차원 전두부 형상을 효과적으로 모델링할 수 있는 열차형상함수를 이용하여 실제 차량인 KTX 산천 전두부 형상의 공기저항을 저감하는 최적설계를 수행하였다. KTX 산천 전두부의 2차원 단면형상의 특성 곡선을 추출하고 열차형상함수를 이용하여 KTX 산천의 최적설계용 유선형 기본형상을 구성하였다. 기본형상을 이용해 상용 고속열차 전두부의 형상 제약조건을 위반하지 않는 설계공간을 구축하였다. Broyden-Fletcher-Goldfarb-Shanno 알고리즘을 이용한 최적설계를 수행하여 기본형상 대비 약 6%의 공기저항을 저감할 수 있었다. 최적형상은 기본형상에 비해 전두부 길이가 길고 끝단이 약간 날카로운 형상을 가져 후미차량에서의 와류의 크기를 줄임으로써 공기저항을 저감하였다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집E
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• pp.373-379
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• 2001

When a train runs into a tunnel at high-speed, aerodynamic drag suddenly increases and the booming noise is generated at the exit of tunnel. The noise shape is very important to reduce the aerodynamic drag in tunnel as well as on open ground, and the micro-pressure wave that is a source of booming noise is dependent on nose shape, especially on area distribution. In this study, the nose shape has been optimized employing the response surface methodology and the axi-symmetric compressible Navier-Stokes equations. The optimal designs have been executed imposing various conditions of the aerodynamic drag and the micro-pressure wave on object functions. The results show that the multi-objective design was successful to decrease micro-pressure wave and aerodynamic drag of trains.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2000년도 추계학술대회 논문집
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• pp.506-513
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• 2000

The tunnel booming noise generated by a train moving into a tunnel has been one of the most serious constraints in the development of the high-speed trains. It is well known that the nose shape of the train has the significant influence on the intensity of the booming noise. In this study, the nose shape has been optimized by using the response surface methodology and the axi-symmetric compressible Euler equations. The parametric studies are also performed with respect to the slenderness ratio, the blockage ratio and the train speed to investigate their sensitivities to the optimization results. The results show that it is possible to define more general design space by introducing the Hicks-Henne shape functions, resulting in the more effective nose shape than that of Maeda. The mechanism and the aspects of the train-tunnel interaction were also investigated from the results of the parametric study.

• 한국구조물진단유지관리공학회 논문집
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• 제20권6호
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• pp.98-105
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• 2016

본 연구에서는 반구형과 평탄형의 비상체를 이용하여 일반콘크리트와 섬유보강콘크리트에 충격시험을 진행한 후 파괴깊이와 형태, 파괴직경, 배면의 인장변형을 평가하였다. 선단면적이 작을수록 충격력의 집중에 의해 파괴깊이는 크고 표면파괴 직경은 작게 되는 것으로 확인되었다. 반면에 선단면적이 클수록 파괴깊이는 작지만 표면파괴직경은 크게 되었다. 일반콘크리트와 섬유보강 콘크리트에서 유사한 표면파괴와 배면변형이 발생하였으나 인장변형의 크기는 일반콘크리트에 비해 섬유보강 콘크리트가 작은 것으로 나타났다. 또한, 비상체의 선단형상에 따른 표면관입의 형태와 배면의 인장변형 사이에 직접적인 연관이 있는 것으로 사료된다. 따라서 콘크리트의 배면박리한계두께 예측 시에는 표면관입깊이뿐만 아니라 배면의 변형거동 또한 고려할 필요성이 있을 것으로 사료된다.